I hope that this not old news and has already been raised by others but I have just come across the following site with a suggested mod to turn an old valve set into an AM transmitter.

http://www.valveradio.net/radio/am-modulator-valve-transmitter.html

It seems a very clever idea and there is a neat kit available on eBay to make the task easier.

I was wondering if any other VR member had seen this and had possibly built it. If so what were the results?

I note that the unnamed owner of site is in Sydney and therefore may be a VR member; is he/she known to anybody?

Andrew

Not so much old news, though that bloke sells those modules on Ebay.

I don't really like the idea of butchering a perfectly good valve radio to make a transmitter, though if there is a sick radio out there with a bashed cabinet, for example, this would work well.

About five or six years ago I got hold of a valve transmitter kit from England which works well and runs on a D cell for the A battery and three 9V batteries in series for the B battery. This also came from Ebay. Unfortunately it is too long ago to remember the name of the seller but a search for valve AM transmitter and similar key words may unearth his username.

I got hold of a valve transmitter kit from England which works well and runs on a D cell for the A battery and three 9V batteries in series for the B battery.

Same here, but I also bought the mains power supply.

Here it is: http://www.6v6.co.uk/tube-transmitter-kits.html

Hi Andrew, of course I had to do it the hard way and made up an "in house" transmitter using all valves typically used in a superhet.
You could make a similar unit with a couple of old junked chassis as the parts source rather than butcher a actual working radio.
In special projects back at the start of 2016 you will find my efforts. I learnt a lot working out how not to do things and came up with a working unit.
Fred.

There have been a variety of units produced over the years. The thing to watch is the frequency they work on and the quality & stability of some unita. Technically one can modulate a signal generator.

I noted that the local "Drive In" in their heyday (long gone) was able to transmit AM to the car radio's (One way of stopping the speaker posts from being towed over) That transmitter I believe, used 807's as the PA.

Yes, that is the one I got.

Have wondered whether it would be possible to convert an AM/FM transistor radio to transmit received FM as AM, given that FM is what may mostly be the program source for an AM transmitter. Such a device would be of inherently low powered as required.

No valves, but....

Such things have been made commercially to tune FM and send it to an AM radio: Very common in USA . These are stand alone units.

I would prefer a host radio diverting audio to a good modulator & PA (transmitter), rather than hack. There are FM valve radios.

I wonder why its not used more often, But 6BL8 (Frequency changer) used as the "universal widget" valve is good for around 200MHz.

Marc

Hello from Jimb.
I have built several different versions of these.
My favourite is the valve version published in Discovering Vintage Radio by Peter Lankshear it was put out by Electronic Australia some years ago.I will try and scan it and would be happy to send it to anyone if they would like it . The article is on page 95 called MATE-A HANDY ACCESSORY .Peter has given several suitable valve alternatives .
i am not sure why but I transformer coupled the audio input circuit the original version is resistive coupled , I am quite sure that would have worked fine . I cannot remember why I decided to change it.it works great and is in regular use. the last one I built was from a kit available from the HRSA costing $27.00 plus $7.00 postage.it was designed by one of the members and also works well, runs from battery. It is advertised as KIT FOR MINI TRANSMITTER. The article was published in their magazine a year or two ago.
Kind Regards.
Jimb

Hi Jimb, if you wind up scanning it, email it to me, that's one I have not seen!
Fred.

Hello Fred.
I have just sent it to you.
Regards Jimb

Received ok!
Fred.

Thanks Fred

Hi Jimb
Could I trouble you to send me a copy also, that would be much appreciated.
I believe my email is not hidden.
Thanks George

Hi Captgogo.
Sorry did not see your request. Happy to send you a copy.
Not home at the should be able to do it this evening.